@media screen and (max-width:800px) and (min-width:600px) {
    /* 600 <= width <= 800px执行下面的语句 */
    h1 {
        color: red;
    }
}

@media screen and (min-width:801px or max-width:500px) {
    /* width>= 801px width<= 500执行下面的语句 */
    h1 {
        color: blue;
    }
}